If PU doesn't really make any difference I don't know where we go from here. I think there is a reasonable amount of evidence that motor oils like Mobil 1 and PU will keep an engine clean if used from the time the engine is new. But it appears we are still looking for that magical cleaner to clean up a dirty engine.
If there is no really effective cleaner than about the only thing that could be done with a really dirty engine is physically clean it up.
Based on what was discovered in Artem's testing I certainly would not pay for Auto-RX+ to try to clean an engine. And Kreen was not effective either. But this engine may be a problem engine and difficult to clean.
I do wish there was some reasonably effective, low cost cleaner that would work. But right now at this time I can't really think of any.
If there is no really effective cleaner than about the only thing that could be done with a really dirty engine is physically clean it up.
Based on what was discovered in Artem's testing I certainly would not pay for Auto-RX+ to try to clean an engine. And Kreen was not effective either. But this engine may be a problem engine and difficult to clean.
I do wish there was some reasonably effective, low cost cleaner that would work. But right now at this time I can't really think of any.